Daily pill helped children with the most common dwarfism grow faster

Children with achondroplasia, the most common form of dwarfism, grew faster over a year when they took an experimental daily pill than when they took a dummy pill, according to a large trial published in the New England Journal of Medicine and highlighted on October 30 by Cincinnati Children’s, one of the trial sites.¹ The drug, called infigratinib, is being developed by BridgeBio Pharma.² If regulators approve it, it would be the first treatment for the condition taken by mouth rather than by injection.¹

What happened

The trial, which BridgeBio calls PROPEL 3, was a Phase 3 study, the last big test before a company asks regulators for approval.² It enrolled 114 children aged 3 to 17 at 27 sites in 10 countries.¹ Children were assigned at random to take either infigratinib or a placebo (a dummy pill) every day for 52 weeks.¹

The study met its main goal, which was to raise how fast children grew in a year.¹ Children on infigratinib grew at a rate of 5.96 centimeters (about 2.3 inches) a year, compared with 4.22 centimeters for those on placebo.¹ BridgeBio described this as the highest average yearly growth rate seen so far in a randomized achondroplasia trial.²

The results were published in the New England Journal of Medicine in June 2026.³ BridgeBio had first announced top results in February 2026.²

The evidence so far

Achondroplasia is caused by overactivity of a growth signal called FGFR3 (fibroblast growth factor receptor 3), which helps control bone growth.¹ Too much FGFR3 activity slows bone development.¹ Infigratinib is a small-molecule drug designed to block FGFR3 signaling.² It was first developed to block the same family of signals in certain cancers.¹

Besides growth speed, researchers looked at height z-scores, a standard way to compare a child’s height with what is expected for children with achondroplasia. Children on the pill improved on this measure.¹ Global Genes, reporting BridgeBio’s figures, said the difference versus placebo was 0.32 standard deviations, and that it was statistically significant.²

The two main accounts give different numbers for the gap between the groups. The Cincinnati Children’s summary says the difference in yearly growth was 1.74 centimeters, which matches subtracting 4.22 from 5.96.¹ The Global Genes report of BridgeBio’s February announcement gives an average improvement of 2.10 centimeters a year over placebo at week 52.² The sources do not explain why the figures differ; it may reflect different ways of analyzing the data.

Side effects appeared at similar rates in the infigratinib and placebo groups, and no serious side effects were judged to be caused by the drug.¹ BridgeBio also reported that no children stopped the drug because of it during the 52 weeks.²

The question of body proportions

Achondroplasia causes disproportionate short stature, meaning the arms and legs are short compared with the trunk.¹ So researchers also measured the ratio of upper body to lower body length. Here the sources describe the result differently.

The Cincinnati Children’s summary says the overall measure of upper-to-lower body ratio did not reach statistical significance, though the effect looked larger in children aged 3 to under 8.¹ BridgeBio, as reported by Global Genes, said a prespecified exploratory analysis (a planned extra look at the data) showed the first statistically significant improvement in body proportions versus placebo in an achondroplasia trial.² Readers should treat the proportion result as uncertain until the full journal data are compared.

What it does not show yet

The trial lasted one year. Researchers note that it cannot answer how tall children will be as adults, how their quality of life changes, or whether the drug affects the medical complications of achondroplasia.¹ These complications can include foramen magnum stenosis, a narrowing at the base of the skull that may need brain surgery.¹ Other complications include obstructive sleep apnea, middle ear problems, a curved upper spine (kyphosis) and spinal stenosis.²

Faster growth during one year is a measure doctors can track, but it is not the same as showing these health problems become less common. An ongoing extension study will keep following children to look at long-term safety and effects.¹ BridgeBio’s research page lists a 2026 conference presentation on longer-term results and another on infants and toddlers, but those data were not part of the sources reviewed for this article.³

Who is behind it

Infigratinib is BridgeBio Pharma’s drug, and the February results and several of the figures above come from the company.² BridgeBio is also targeting a related condition, hypochondroplasia.² Daniela Rogoff, BridgeBio’s chief medical officer for skeletal dysplasia, said the data support the potential of an oral medicine directly targeting FGFR3 overactivity.²

The Cincinnati Children’s article was written by Benjamin Cocanougher, a medical geneticist there and the hospital’s lead investigator for the trial.¹ He said:

“These results suggest an oral therapy may be as effective or more effective than current injectable therapies and provide another option for children and families.”¹

That comparison with injections is his view. This trial tested the pill against a dummy pill, not against an injected drug, so the sources do not show a head-to-head comparison.¹

How it fits the field

Treatment options for achondroplasia have grown in recent years, but approved therapies all require injections.¹ Cincinnati Children’s says the FDA-approved options are given by daily or weekly injection.¹ Global Genes, writing in February, described BioMarin’s Voxzogo, a once-daily injection that promotes bone growth, as the only approved drug for children with achondroplasia whose growth plates are still open.²

The infigratinib program has been building for several years. BridgeBio’s research page lists a 2024 mouse study in which low doses increased bone growth, and an earlier New England Journal of Medicine paper from November 2024 on the drug in children.³ Cocanougher pointed to the drug’s cancer origins as an example of how work in one area of medicine can open options in rare genetic diseases, where small patient numbers can make investment hard.¹

What to watch next

• Regulatory filings. In February, BridgeBio said it would meet with regulators about submitting applications to sell infigratinib in the United States and Europe in the second half of 2026.² Whether those filings are made and accepted is the next concrete step.
• Longer-term data. The extension study will show whether faster growth continues and whether safety holds over time.¹
• Younger children. The trial hinted at bigger effects in children under 8, and BridgeBio has presented work in infants and toddlers.¹³

For now, the strongest evidence is one year of controlled data in 114 children showing faster growth on the pill than on placebo, with similar side-effect rates.¹ What that means for adult height and health is still unknown.